diff --git a/vm/src/stdlib/ast.rs b/vm/src/stdlib/ast.rs
index 7d1f49a024..d3bdd3656b 100644
--- a/vm/src/stdlib/ast.rs
+++ b/vm/src/stdlib/ast.rs
@@ -624,8 +624,8 @@ fn ast_parse(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
 pub fn mk_module(ctx: &PyContext) -> PyObjectRef {
     py_module!(ctx, "ast", {
         "parse" => ctx.new_rustfunc(ast_parse),
-        "Module" => ctx.new_class("_ast.Module", ctx.object()),
-        "FunctionDef" =>ctx.new_class("_ast.FunctionDef", ctx.object()),
-        "Call" => ctx.new_class("_ast.Call", ctx.object())
+        "Module" => py_class!(ctx, "_ast.Module", ctx.object(), {}),
+        "FunctionDef" => py_class!(ctx, "_ast.FunctionDef", ctx.object(), {}),
+        "Call" => py_class!(ctx, "_ast.Call", ctx.object(), {})
     })
 }
diff --git a/vm/src/stdlib/io.rs b/vm/src/stdlib/io.rs
index 12b85e6604..f35d5eb041 100644
--- a/vm/src/stdlib/io.rs
+++ b/vm/src/stdlib/io.rs
@@ -347,10 +347,10 @@ pub fn io_open(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
 
 pub fn mk_module(ctx: &PyContext) -> PyObjectRef {
     //IOBase the abstract base class of the IO Module
-    let io_base = ctx.new_class("IOBase", ctx.object());
+    let io_base = py_class!(ctx, "IOBase", ctx.object(), {});
 
     // IOBase Subclasses
-    let raw_io_base = ctx.new_class("RawIOBase", ctx.object());
+    let raw_io_base = py_class!(ctx, "RawIOBase", ctx.object(), {});
 
     let buffered_io_base = py_class!(ctx, "BufferedIOBase", io_base.clone(), {
         "__init__" => ctx.new_rustfunc(buffered_io_base_init)
diff --git a/vm/src/stdlib/os.rs b/vm/src/stdlib/os.rs
index ef45d2d84a..5379fefc4d 100644
--- a/vm/src/stdlib/os.rs
+++ b/vm/src/stdlib/os.rs
@@ -119,17 +119,17 @@ fn os_error(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
 }
 
 pub fn mk_module(ctx: &PyContext) -> PyObjectRef {
-    let py_mod = ctx.new_module(&"os".to_string(), ctx.new_scope(None));
-    ctx.set_attr(&py_mod, "open", ctx.new_rustfunc(os_open));
-    ctx.set_attr(&py_mod, "close", ctx.new_rustfunc(os_close));
-    ctx.set_attr(&py_mod, "error", ctx.new_rustfunc(os_error));
-
-    ctx.set_attr(&py_mod, "O_RDONLY", ctx.new_int(0));
-    ctx.set_attr(&py_mod, "O_WRONLY", ctx.new_int(1));
-    ctx.set_attr(&py_mod, "O_RDWR", ctx.new_int(2));
-    ctx.set_attr(&py_mod, "O_NONBLOCK", ctx.new_int(4));
-    ctx.set_attr(&py_mod, "O_APPEND", ctx.new_int(8));
-    ctx.set_attr(&py_mod, "O_CREAT", ctx.new_int(512));
+    let py_mod = py_module!(ctx, "os", {
+        "open" => ctx.new_rustfunc(os_open),
+        "close" => ctx.new_rustfunc(os_close),
+        "error" => ctx.new_rustfunc(os_error),
+        "O_RDONLY" => ctx.new_int(0),
+        "O_WRONLY" => ctx.new_int(1),
+        "O_RDWR" => ctx.new_int(2),
+        "O_NONBLOCK" => ctx.new_int(4),
+        "O_APPEND" => ctx.new_int(8),
+        "O_CREAT" => ctx.new_int(512)
+    });
 
     if cfg!(windows) {
         ctx.set_attr(&py_mod, "name", ctx.new_str("nt".to_string()));
diff --git a/vm/src/stdlib/weakref.rs b/vm/src/stdlib/weakref.rs
index 5b67f1664e..ba6015ec21 100644
--- a/vm/src/stdlib/weakref.rs
+++ b/vm/src/stdlib/weakref.rs
@@ -13,13 +13,14 @@ use crate::VirtualMachine;
 use std::rc::Rc;
 
 pub fn mk_module(ctx: &PyContext) -> PyObjectRef {
-    let py_mod = ctx.new_module("_weakref", ctx.new_scope(None));
+    let py_ref_class = py_class!(ctx, "ref", ctx.object(), {
+        "__new__" => ctx.new_rustfunc(ref_new),
+        "__call__" => ctx.new_rustfunc(ref_call)
+    });
 
-    let py_ref_class = ctx.new_class("ref", ctx.object());
-    ctx.set_attr(&py_ref_class, "__new__", ctx.new_rustfunc(ref_new));
-    ctx.set_attr(&py_ref_class, "__call__", ctx.new_rustfunc(ref_call));
-    ctx.set_attr(&py_mod, "ref", py_ref_class);
-    py_mod
+    py_module!(ctx, "_weakref", {
+        "ref" => py_ref_class
+    })
 }
 
 fn ref_new(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
diff --git a/wasm/lib/src/browser_module.rs b/wasm/lib/src/browser_module.rs
index ea21d30fda..9a80be0c9a 100644
--- a/wasm/lib/src/browser_module.rs
+++ b/wasm/lib/src/browser_module.rs
@@ -313,12 +313,10 @@ fn browser_prompt(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
 const BROWSER_NAME: &str = "browser";
 
 pub fn mk_module(ctx: &PyContext) -> PyObjectRef {
-    let promise = {
-        let promise = ctx.new_class("Promise", ctx.object());
-        ctx.set_attr(&promise, "then", ctx.new_rustfunc(promise_then));
-        ctx.set_attr(&promise, "catch", ctx.new_rustfunc(promise_catch));
-        promise
-    };
+    let promise = py_class!(ctx, "Promise", ctx.object(), {
+        "then" => ctx.new_rustfunc(promise_then),
+        "catch" => ctx.new_rustfunc(promise_catch)
+    });
 
     py_module!(ctx, BROWSER_NAME, {
         "fetch" => ctx.new_rustfunc(browser_fetch),